Keysight Technologies, Inc.
SIGNAL RECEIVER INCLUDING DIGITAL IMAGE SIGNAL SEPARATION

Abstract:

A method of frequency-converting a received radio frequency (RF) signal includes frequency mixing a received RF signal with a first local oscillator (LO) signal to generate a first intermediate frequency (IF) signal, where the first IF signal is a mixed signal of a desired signal and an image signal. The method further includes frequency mixing the RF signal with a second LO signal to generate a second IF signal, where the second LO signal has a same frequency as the first LO signal, and the second LO signal has a 90 degree phase shift relative to the first LO signal. The method further includes analog-to-digital converting the first IF signal to a first digital signal and the second IF signal to a second digital signal, down-converting the first digital signal to a first digital baseband signal and the second digital signal to a second digital baseband signal, calibrating the first and second digital baseband signals for the 90 degree phase shift, and the separating the calibrated first and second digital baseband signals to obtain the desired signal and the image signal.